The present invention relates to circuit packages and, more particularly, to leadless integrated circuit packages for supporting integrated circuit chips and connector receptacles for receiving such packages.
Leadless integrated circuit packages are commonly used for mounting integrated circuits on printed circuit boards, computer backpanels, and the like, and have significant advantages over conventional dual in-line packages (DIP's) and single in-line packages (SIP's) in the manufacture of large electronic systems, such as computers. If, during the assembly of integrated circuits on a computer backpanel, there is discovered a defect in one of the integrated circuits, the leadless package having the defective integrated circuit is simply removed from its receptacle and replaced with a new package. There is thereby eliminated the problem of removing packages having soldered leads or pins, and the potential for bending or breaking such pins when removed.
As is the case with any integrated circuit package, whether leadless or not, there is a practical limitation on the number of external connections that can be made to the package and chip, such limitation largely depending on the physical dimensions of the package. A leadless package typically has an insulating substrate or layer and a plurality or set of conductors on the layer extending between connector coupling edges about the periphery of the layer and a center or central location of the package where the integrated circuit chip is supported. These conductors provide electrical connections to the chip, but must be limited in number since each conductor requires a certain amount of surface area on the layer.
Advances in integrated circuit technology have resulted in increased circuit densities and, in turn, increased numbers of circuit functions that can be provided on a single integrated circuit chip. However, such increases in the number of functions often require additional external electrical connections to the chip. In the past, the only apparent way in which the number of external connections could be increased was generally to increase the size or surface area of the package so that more conductors would be provided between the connector coupling edges of the insulating layer and the integrated circuit layer. Increasing the size of the package, however, also increases the amount of area required for each package on a circuit board or backpanel, and thus eliminates some of the space savings achieved by the increased circuit density of the chip itself.